This invention relates to surgery and more particularly relates to illumination devices particularly suited for ophthalmic surgery and the like.
It is known that ophthalmic surgery (and other types of surgery such as laparoscopic and arthroscopic surgery) as well as various procedures such as endoscopy typically require an illumination probe or device which provides illumination for the area under treatment. To provide the best possible visualization for the physician/user of the device, it is preferred that the output of the illumination device be broadband (simulating sunlight to some degree), that the device itself be rather small (so as to not interfere with other instruments being used in the procedure, for example), that the device illuminate a relatively large area at one time, that the light output over the illuminated area be fairly uniform (eliminating dark spots, excessively bright spots, etc.) and not project back towards the operator so as to cause glare that interferes with viewing.
Often the illumination is transmitted from an illumination source (disposed at some distance from the patient) through an optical fiber cable to a handpiece which is manipulated by the physician/user or an assistant to provide illuminating light on the desired area. Optical fiber cables do a good job of providing broad spectrum light from a suitable illumination source, but the light output of optical fibers could be improved. For example, the numerical aperture of optical fibers are typically rather small, with the result that the field of illumination for these devices is smaller than could be desired. Moreover, these devices are most often used in liquids (saline solutions and the like) which further reduces the field of illumination. A narrow field of illumination is adequate for conventional ophthalmic surgical viewing systems, but recently viewing systems have been developed which give the surgeon a more panoramic view of the eye, and require greater dispersion of light to illuminate this larger area. To more uniformly disperse the illumination, lenses have been used as the end of the optical fiber to spread the light. Moreover, at least one device (manufactured by Trek Medical) has been proposed to spread the light by changing the distal configuration of the optical fiber itself from the standard blunt shape to a cone shape. Infinitech, Inc., licensee of the present invention, has also developed a distal configuration of the optical fiber (shown in U.S. Pat. No. 5,351,168) which is believed to address the problem of dispersing the light in a superior manner.
All these devices could be improved however. For example, it has been found that the wide angle illumination devices such as those described above result in light from the illumination probe being transmitted directly into the surgeon's eyes. This, of course, is undesirable and somewhat defeats the purpose of having a wide angle illumination device. This problem makes fine structures adjacent to the probe (e.g. vitreous fibers) quite difficult to see. In addition, glare from the probe becomes increasingly problematic in a gas-filled eye or with poor media. What would be preferred in some instances is a wide angle illumination device which provides means for protecting the surgeon's eyes from direct illumination so as to not affect the surgeon's view of the surgical area.